This invention relates to a closure for protection of a connection section or splicing section of a communication cable such as an optical fiber cable or the like, and more particularly to an improvement in a closure for cable connection for an optical fiber cable.
In general, a closure for cable connection includes end plates through which cables with a cable connection section being interposed therebetween are inserted and a cylindrical sleeve formed of two split parts so as to cover the cable connection section and constructed in a manner to be split in a longitudinal direction. The two parts for the sleeve arranged between the end plates are joined to each other through abutting portions thereof opposite to each other using any suitable fixing means such as a bolt, a band or the like, resulting in providing the sleeve for airtightly protecting the cable connection section.
The conventional sleeve thus constructed for protecting the cable connection section is required to exhibit rigidity sufficient to prevent deformation of the sleeve and properties sufficient to prevent intrusion of moisture thereinto. For this purpose, the sleeve is so constructed that components of the sleeve are intimately or tightly coupled to each other and coupling between the cable and the sleeve is likewise tightly carried out. Unfortunately, such construction of the conventional sleeve causes setting of the cable led out of the end plates and handling of the sleeve to be substantially troublesome. Also, the conventional sleeve has another disadvantage of requiring a cable storage provided with an airtight member in order to ensure sufficient fastening of the cable. However, this renders manufacturing of the sleeve troublesome and costly and deteriorates durability of the sleeve. Further, in order to ensure that the conventional sleeve exhibits satisfactory airtightness, force for fastening the end plates must be strictly controlled and assembling of the sleeve is rendered laborious and time-consuming.
In the conventional closure, a support wire or a cable, such as an aerial wire, a trunk cable or the like is fixed in the closure by a cable clamp. The cable clamp is formed with cable guide recesses each of which permits a cable of a maximum diameter to be fitted therein. Accordingly, when a cable of a small diameter is fixed by such a cable clamp, it is necessary to interpose a spacer or bush of a predetermined size between the cable and the cable guide recess or to wind a required number of turns of a tape having a certain thickness around the cable.
Such adjustment of an outer diameter of the cable with respect to the cable guide recess has conventionally been carried out at site, and thus replacement of the spacer or rewinding of the tape is highly troublesome. In addition, it is necessary to keep a number of spacers or bushes which have cable inserting holes of different diameters in correspondence to cables of various outer diameters and to select among them.